Gamma Knife Overview

Gamma Knife stereotactic radiosurgery is a well-established treatment method used to treat several conditions or diseases affecting the brain. In clinical use since 1968, 500,000 patients have been treated worldwide. Over 60,000 patients are treated with Gamma Knife radiosurgery each year, worldwide.

The Gamma Knife, however, isn't a knife at all. It uses gamma rays produced by 192 cobalt-60 radiation sources to precisely target and destroy abnormalities within the brain.

The result is like a pinpoint of radiation so small and powerful it can reach the specific part of the brain that needs treatment without destroying healthy surrounding tissue. The doctor makes no incisions in your head and the treatment itself is painless.

Your head is held firmly and securely in a head frame while you enter the Gamma Knife machine. With the frame placement there is some discomfort, but local pain medicine makes this minimal. Patients usually say the frame looks far worse than the actual experience.

How it Works

The method of treatment is unique. Once your individual plan is completed, the actual radiation can start. The frame adapter is attached and the patient will lie down on the treatment couch. Within the Gamma Knife are 192 precisely directed cobalt sources that emit gamma radiation to a precise target area in the brain.

The frame adapter immobilizes the patient's head and moves it from position to position. This automatic positioning helps expedite the procedure and allows treatment of the lesion with pinpoint accuracy.

The individual beams are too weak to damage healthy tissue on their way to the target area, but become very powerful as they simultaneously merge at a single focal point. By placing a patient's head in one or several positions, the shape and dose of radiations is optimized to affect only the target, avoiding any damage to the surrounding healthy tissue. In most cases, patients receive a single treatment.

Preparing for Gamma Knife Radiosurgery

You will be scheduled for a consultation with a Radiation Oncologist and Neurosurgeon for a physical examination and to review your medical history and past and recent films. If it is determined that Gamma Knife is the best treatment for you, a treatment date will be scheduled.

Once your treatment date is determined, you should not eat or drink after midnight the night before the procedure. You are to take your medication the morning of the procedure with small sips of water. Please bring a list of your current medications and any you may need to take the day of the procedure.

If you are diabetic or on blood thinners please let your physician know so modifications can be made if needed.

On the day of the procedure, you need to register at Patient Services on the 3rd floor of the Center for Advanced Medicine and then go to the waiting room of Radiation Oncology on the lower level where you will be greeted by the Gamma Knife nursing staff. You and one or two members of your family will be taken to the Gamma Knife area.

You will change into comfortable clothing for the treatment. A series of questions will be reviewed and an IV will be inserted. Monitoring equipment will be attached during frame placement.

Your neurosurgeon will interview you again to evaluate any changes that may have occurred since consultation.

The Treatment Process

The treatment consists of four main steps - attaching the frame, imaging, treatment planning and treatment. During the procedure different members of the team; consisting of a neurosurgeon, radiation oncologist, medical physicist, neuroscience nurse and radiation therapist, will monitor your care and you most likely will remain awake at all times. If you have a favorite music CD you may use it during treatment.

Attaching the Frame: To begin the procedure, your neurosurgeon will spend a few minutes placing your head in a lightweight frame. Your hair does not need to be cut or shaved. A local anesthetic will be applied where the frame is to be attached. You will experience some discomfort for a short period of time from the injections of anesthetic. Once the anesthetic has taken effect, the frame is secured with four screws that pierce your skin and go tightly against your skull, in order to stabilize your position during imaging and treatment. Your head will remain in the frame throughout the entire procedure. Once your head frame is in place and measurements are taken, it's time for imaging.
Imaging: A coordinate box is used during imaging to provide reference points on the images for the treatment plan. Although you may have previously done these imaging studies, they need to be completed with the frame on to precisely define the location, size and shape of the area to be treated. Once the images are done they are transferred to a sophisticated treatment-planning computer.
Treatment Planning: Then as you rest, read or watch TV, your neurosurgeon, radiation oncologist and medical physicist will prepare a three-dimensional treatment plan customized for your condition utilizing specially designed software. Once this plan is re-checked and approved, treatment can begin.
Treatment: Your doctor will then tell you how long the actual procedure will take. The treatment itself is totally silent and painless. The frame adapter is attached and the patient will lie down on the treatment couch. During the course of your treatment, you will remain fully awake and can communicate with your radiation therapist and nurse through an audio/video connection. And remember, members of your team are close at hand to assist if needed.

Once you've finished treatment, the frame will be removed. Occasionally; when the frame is removed, some patients experience a slight headache or mild swelling where the frame was attached. For most patients, there is no such effect.

You will be given discharge instructions and depending on your specific diagnosis and areas treated, your doctor will discuss with you and your family any precautions or possible side-effects that may occur as well as treatment options for them.

Your doctor will schedule follow-up visits and consultations, some with repeat MRI or CAT scans, to monitor your progress. Because the effects of treatment occur over time, it may take weeks or even months to see the full results of your treatment. As always, consult your doctor should you have any questions or concerns regarding your condition.

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